Towards a scalable software-defined network virtualization platform

Software-defined networking (SDN) has emerged to circumvent the difficulty of introducing new functionality into the network. The widespread adoption of SDN technologies, such as OpenFlow, can facilitate the deployment of novel network functions and new services. Network infrastructure providers can significantly benefit from the SDN paradigm by leasing network slices with SDN support to Service Providers and end-users. Currently, the deployment of arbitrary virtual SDN topologies entails significant configuration overhead for SDN operators. To this end, we present a SDN virtualization layer that orchestrates the deployment and management of virtual SDNs (vSDN). The so-called SDN hypervisor generates and installs the forwarding entries required for vSDN setup and also coordinates the necessary switch flow table modifications for seamless resource migration. Furthermore, the hypervisor transparently rewrites all control messages enforcing flowspace isolation while giving to the vSDN operator the illusion of exclusive access control. We explore the design space and prerequisites for SDN virtualization, including the selection and encoding of packet identifiers, the resolution of flowspace identifiers, and the configuration and consolidation of multiple virtual flow tables onto a single switch in order to provide support for arbitrary topologies. Furthermore, we discuss the scalability of the SDN control and data plane.